In a typical cellular system, also referred to as a wireless communications network, wireless terminals, also known as mobile stations and/or user equipment units communicate via a Radio Access Network (RAN) to one or more core networks. The wireless terminals can be mobile stations or user equipment units such as mobile telephones also known as “cellular” telephones, and laptops with wireless capability, e.g., mobile termination, and thus can be, for example, portable, pocket, hand-held, computer-comprised, or car-mounted mobile devices which communicate voice and/or data with radio access network.
The radio access network covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a Radio Base Station (RBS), which in some networks is also called “NodeB” or “B node” and which in this document also is referred to as a base station. A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. Each cell is identified by an identity within the local radio area, which is broadcast in the cell. The base stations communicate over the air interface operating on radio frequencies with the user equipment units within range of the base stations.
In some versions of the radio access network, several base stations are typically connected, e.g., by landlines or microwave, to a Radio Network Controller (RNC). The radio network controller, also sometimes termed a Base Station Controller (BSC), supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile communication system, which evolved from the Global System for Mobile Communications (GSM), and is intended to provide improved mobile communication services based on Wideband Code Division Multiple Access (WCDMA) access technology. UMTS Terrestrial Radio Access Network (UTRAN) is essentially a radio access network using wideband code division multiple access for user equipment units (UEs). The Third Generation Partnership Project (3GPP) has undertaken to evolve further the UTRAN and GSM based radio access network technologies. Long Term Evaluation (LTE) together with Evolved Packet Core (EPC) is the newest addition to the 3GPP family.
Policy and Charging Control (PCC) was originally introduced in 3GPP standards as a mean to secure resources in the access network mainly for dynamic services (such as IMS), but also to control resource consumption for regular Internet services (P2P-traffic, web-browsing, FTP etc) and to enable Flow Based Charging (FBC).
Although the original goal with PCC has since long time been completed in 3GPP, there is still a lot of activities ongoing in standards enhancing the PCC framework with add-ons. The new functions amended to the PCC architecture have shifted the role of the PCRF from something that was originally just a requirement for IMS into a more fundamental system element.
From the very beginning the reference point between the PCRF and the access network has been the Gx interface, as shown in FIG. 1. All input data from the access network had to be passed over this interface. For dynamic services, e.g. IMS, the Rx reference point was also defined for scalability purposes i.e. to be able to have stand-alone P-CSCF and PCRF functions.
From 3GPP Release-11 we now have (as illustrated in FIG. 2) a: Gx between the PCEF and the PCRF; Rx between the PCRF and the AF; Gxx between the PCRF and the BBERF (e.g. SGW); Ud between the PCRF-FE and the UDR; Sy between the PCRF and the OCS; and Sd between the PCRF and the TDF.
To summarize all of this the Release-11 PCRF in comparison to e.g. a Release-7 PCRF has significantly better capabilities to collect input information for performing policy decisions. Policy decisions can now be made based on (not a complete list): User subscription information (From Rel-7); Access Network Specific information (from Rel-7); IMS authorized services (Rel-7); Consumed volume usage (Rel-9); 3rd party sponsorship of a service (Rel-10); Actual service used (Rel-11); Subscription defined spending limits (Rel-11).
All of this input information still serves the same purpose though and that is to be able to provide differentiated treatment (i.e. personalization) for user plane packets.